I want to ask, “他演讲得很精彩”, is this sentence correct or not? Is “演讲” a verb or a noun?
他演讲得很精彩 sounds unnatural because we mainly use 演讲 as a noun for 'speech'. It is also possible to use it as a verb for 'to make a speech' in some context, e.g. 明天要上台演讲 (have to go on stage to make a speech tomorrow)
Use 演讲 as a noun and say "他的演讲很精彩" is the most natural way to phrase it.
If you must use 演讲 as a verb, it is more natural to say 他演讲讲得很精彩 or simply "(這次演讲 - implied topic)他讲得很精彩"
In most cases, the verb 演讲 can be reduced to just 讲
明天要上台演讲黑暗物質的理論 --> 明天要上台讲黑暗物質的理論 (when you speak on a stage, it is giving a lecture/ speech)
In terms of grammar, it is correct.
演講can be either a verb ('to lecture') or a noun ('lecture'); here it is a verb. It means 'He lectures wonderfully'.
Personally I would phrase it like
他的演講很精彩('His lecture was wonderful'). Although nominalisation is a feature of westernised Chinese (歐化中文), it is okay when used sparingly and properly. That is to say this is a matter of style, not of grammar.
Based on the corresponding English grammar, this sentence is correct.
"演讲" is a verb. We judge it by the word "得", which is usually just after the verb.
However, I would like to say "他讲得很精彩" and "他的演讲很精彩" instead of "他演讲得很精彩".
演讲 means that lots of people seriously listen professional talk about something in a hall.
We view this a bit formal scenario as a noun in Chinese.
If our emphasis is 精彩, a formal word to illustrate this talk is redundant, 讲 is completely okay.
If our point is indeed the presentation itself, as I said, 演讲 should act as a noun.
演 and 讲 both are verbs if used separately, but together, 演讲 (an event), is a noun. The example sentence essentially has no verb, thus, while understandable, it is not Grammarly correct, nor sounded good.
The correct way should be 他的演讲說得很精彩, in which 說 is the verb. Or 他讲得很精彩, here, 讲 is the verb.